A 17- year- old boy has pus- filled cysts on his face and upper back. Microscopic examination reveals gram- positive rods. This infection is caused by

Question

Quizplus · Accepted Answer

The presence of pus-filled cysts on the face and upper back suggests acne. Gram-positive rods are not commonly associated with acne and the most likely causative agent is Propionibacterium acnes, a gram-positive anaerobic bacterium that is part of the normal skin flora.

A 17- Year- Old Boy Has Pus- Filled Cysts on His